484 research outputs found

    Pattern operators for grid

    Get PDF
    The definition and programming of distributed applications has become a major research issue due to the increasing availability of (large scale) distributed platforms and the requirements posed by the economical globalization. However, such a task requires a huge effort due to the complexity of the distributed environments: large amount of users may communicate and share information across different authority domains; moreover, the “execution environment” or “computations” are dynamic since the number of users and the computational infrastructure change in time. Grid environments, in particular, promise to be an answer to deal with such complexity, by providing high performance execution support to large amount of users, and resource sharing across different organizations. Nevertheless, programming in Grid environments is still a difficult task. There is a lack of high level programming paradigms and support tools that may guide the application developer and allow reusability of state-of-the-art solutions. Specifically, the main goal of the work presented in this thesis is to contribute to the simplification of the development cycle of applications for Grid environments by bringing structure and flexibility to three stages of that cycle through a commonmodel. The stages are: the design phase, the execution phase, and the reconfiguration phase. The common model is based on the manipulation of patterns through pattern operators, and the division of both patterns and operators into two categories, namely structural and behavioural. Moreover, both structural and behavioural patterns are first class entities at each of the aforesaid stages. At the design phase, patterns can be manipulated like other first class entities such as components. This allows a more structured way to build applications by reusing and composing state-of-the-art patterns. At the execution phase, patterns are units of execution control: it is possible, for example, to start or stop and to resume the execution of a pattern as a single entity. At the reconfiguration phase, patterns can also be manipulated as single entities with the additional advantage that it is possible to perform a structural reconfiguration while keeping some of the behavioural constraints, and vice-versa. For example, it is possible to replace a behavioural pattern, which was applied to some structural pattern, with another behavioural pattern. In this thesis, besides the proposal of the methodology for distributed application development, as sketched above, a definition of a relevant set of pattern operators was made. The methodology and the expressivity of the pattern operators were assessed through the development of several representative distributed applications. To support this validation, a prototype was designed and implemented, encompassing some relevant patterns and a significant part of the patterns operators defined. This prototype was based in the Triana environment; Triana supports the development and deployment of distributed applications in the Grid through a dataflow-based programming model. Additionally, this thesis also presents the analysis of a mapping of some operators for execution control onto the Distributed Resource Management Application API (DRMAA). This assessment confirmed the suitability of the proposed model, as well as the generality and flexibility of the defined pattern operatorsDepartamento de Informática and Faculdade de Ciências e Tecnologia of the Universidade Nova de Lisboa; Centro de Informática e Tecnologias da Informação of the FCT/UNL; Reitoria da Universidade Nova de Lisboa; Distributed Collaborative Computing Group, Cardiff University, United Kingdom; Fundação para a Ciência e Tecnologia; Instituto de Cooperação Científica e Tecnológica Internacional; French Embassy in Portugal; European Union Commission through the Agentcities.NET and Coordina projects; and the European Science Foundation, EURESCO

    Pattern Operators for Grid Environments

    Get PDF
    The definition and programming of distributed applications has become a major research issue due to the increasing availability of (large scale) distributed platforms and the requirements posed by the economical globalization. However, such a task requires a huge effort due to the complexity of the distributed environments: large amount of users may communicate and share information across different authority domains; moreover, the “execution environment” or “computations” are dynamic since the number of users and the computational infrastructure change in time. Grid environments, in particular, promise to be an answer to deal with such complexity, by providing high performance execution support to large amount of users, and resource sharing across different organizations. Nevertheless, programming in Grid environments is still a difficult task. There is a lack of high level programming paradigms and support tools that may guide the application developer and allow reusability of state-of-the-art solutions. Specifically, the main goal of the work presented in this thesis is to contribute to the simplification of the development cycle of applications for Grid environments by bringing structure and flexibility to three stages of that cycle through a commonmodel. The stages are: the design phase, the execution phase, and the reconfiguration phase. The common model is based on the manipulation of patterns through pattern operators, and the division of both patterns and operators into two categories, namely structural and behavioural. Moreover, both structural and behavioural patterns are first class entities at each of the aforesaid stages. At the design phase, patterns can be manipulated like other first class entities such as components. This allows a more structured way to build applications by reusing and composing state-of-the-art patterns. At the execution phase, patterns are units of execution control: it is possible, for example, to start or stop and to resume the execution of a pattern as a single entity. At the reconfiguration phase, patterns can also be manipulated as single entities with the additional advantage that it is possible to perform a structural reconfiguration while keeping some of the behavioural constraints, and vice-versa. For example, it is possible to replace a behavioural pattern, which was applied to some structural pattern, with another behavioural pattern. In this thesis, besides the proposal of the methodology for distributed application development, as sketched above, a definition of a relevant set of pattern operators was made. The methodology and the expressivity of the pattern operators were assessed through the development of several representative distributed applications. To support this validation, a prototype was designed and implemented, encompassing some relevant patterns and a significant part of the patterns operators defined. This prototype was based in the Triana environment; Triana supports the development and deployment of distributed applications in the Grid through a dataflow-based programming model. Additionally, this thesis also presents the analysis of a mapping of some operators for execution control onto the Distributed Resource Management Application API (DRMAA). This assessment confirmed the suitability of the proposed model, as well as the generality and flexibility of the defined pattern operatorsDepartamento de Informática and Faculdade de Ciências e Tecnologia of the Universidade Nova de Lisboa; Centro de Informática e Tecnologias da Informação of the FCT/UNL; Reitoria da Universidade Nova de Lisboa; Distributed Collaborative Computing Group, Cardiff University, United Kingdom; Fundação para a Ciência e Tecnologia; Instituto de Cooperação Científica e Tecnológica Internacional; French Embassy in Portugal; European Union Commission through the Agentcities.NET and Coordina projects; and the European Science Foundation, EURESCO

    Consumo Consciente: repensando a sociedade de consumo e novas práticas socioambientais e culturais

    Get PDF
    O Consumo Consciente nasce da constatação da insustentabilidade do modelo socioeconômico vigente, polarizado entre o consumo excessivo e a impossibilidade de atendimento de necessidades básicas. Nesta dissertação investigaremos a configuração do consumo em sua centralidade na contemporaneidade através da pesquisa sobre a constituição histórica da Sociedade de Consumo, da formação da consciência social e ambiental atreladas a práticas de consumo, de caminhos e teorias em prol de mudanças estruturais que propõe novos modelos de Produção (Economia Circular), Economia (Decrescimento), Design de Comunidades (Permacultura) e Estruturação Empresarial (Empresas B). Através do estudo de caso da Rede Asta analisaremos como o Consumo Consciente e outras práticas sustentáveis geram impactos positivos para a sociedade e para o meio ambiente. Assim, a presente dissertação apresentará diversificadas facetas que envolvem o Consumo Consciente como um campo repleto de propostas inovadoras no âmbito da sustentabilidade.The Conscious Consumption has grown in the heart of the unsustainability of the current socioeconomic model, polarized between excessive consumption, in one side, and the impossibility to supply the basic needs, in the other. In this dissertation we investigate the configuration of the contemporary consumption in its centrality through the research about the historical constitution of the Consumer Society, the formation of social and environmental awareness linked to consumption practices, paths and theories in favor of structural changes that proposes new ways of life, based on new concepts of Production (Circular Economic), Economics (Degrowth), Community Design (Permaculture) and Business Structuring (B Corporations). Through the case study of Rede Asta we will analyze how Conscious Consumption and other sustainable practices generates positive environmental and social impacts. Thereby, this dissertation will present diversified facets involving Conscious Consumption as a field full of innovative proposals in the scope of sustainability

    Accessing Wireless Sensor Networks Via Dynamically Reconfigurable Interaction Models

    Get PDF
    The Wireless Sensor Networks (WSNs) technology is already perceived as fundamental for science across many domains, since it provides a low cost solution for environment monitoring. WSNs representation via the service concept and its inclusion in Web environments, e.g. through Web services, supports particularly their open/standard access and integration. Although such Web enabled WSNs simplify data access, network parameterization and aggregation, the existing interaction models and run-time adaptation mechanisms available to clients are still scarce. Nevertheless, applications increasingly demand richer and more flexible accesses besides the traditional client/server. For instance, applications may require a streaming model in order to avoid sequential data requests, or the asynchronous notification of subscribed data through the publish/subscriber. Moreover, the possibility to automatically switch between such models at runtime allows applications to define flexible context-based data acquisition. To this extent, this paper discusses the relevance of the session and pattern abstractions on the design of a middleware prototype providing richer and dynamically reconfigurable interaction models to Web enabled WSNs

    Aristóteles: De Anima

    Get PDF

    O diálogo "Fedro" de Platão como meta-dialético

    Get PDF
    This essay’s aim is to show that Plato’s Phaedrus displays an ingenious dramatic structure: Socrates prescribes the dialetic as the best “art in conducting souls” and, at the same time, obtains the real conversion of Phaedrus to Philosophy. More than a dramatic narrative, the dialogue stages this conversion, making its agents to perform and make effective in the field of their actions the themes that are being enunciated in theis speeches.O objetivo deste ensaio é mostrar que o Fedro de Platão exibe uma engenhosa estrutura dramática: Sócrates prescreve a dialética como a melhor “arte na condução das almas” e a um só tempo realiza a verdadeira conversão de Fedro à Filosofia. Porém, mais do que apenas uma narrativa dramática, o diálogo encena essa conversão fazendo seus agentes performarem e efetivarem no plano de suas ações os temas que estão sendo enunciados em seus discursos

    Aspectos cênicos do diálogo Protágoras de PLatão

    Get PDF
    Aspectos cênicos do diálogo Protágoras de PLatã

    Tracking participants’ behaviour when performing linguistic tasks

    Get PDF
    This study aims to identify behaviours that accompany the psychological processes involved in reading sentences and deciding on a response. The response times of different participants' actions while they completed a questionnaire were measured. We focus on two datasets from the sample: cases in which participants changed their responses and cases in which they did not. The results show that changing the response has an impact on response times. More importantly, this impact occurs not only during the decision-making process but also throughout the task. This research may contribute to a better understanding of response time data in off-line techniques and to fine-tuning experimental designs.Research at the Centre for Humanistic Studies (CEHUM) was funded by FCT Foundation for Science and Technology (CEECIND/04331/2017). FCT has funded the research partially at CMAT (UIDB/00013/2020, UIDP/00013/2020) and the research at NIPE (UIDB/03182/2020)
    corecore